With present day standard printing processes, the original image must be converted into a raster pattern of some type with the raster pattern forming the print master. The resolution is a function of the resolution of the raster and, in many cases, the poor resolution resulting from the need for a raster, i.e. a dot pattern or like half-tone screen, results in poor rendition.
Because of the requirement for a raster or half-tone screen of this type, in offset printing, the various colors cannot be mixed at will. For each color, for example, a different angular setting of the raster is required.
With angular offsets between colors of less than 30.degree., moire patterns tend to be formed. This can be acceptable when, for example, only four colors are to be printed. However, in the case of art prints, so-called support colors must be printed together with other colors and it is difficult to provide the requisite angular offsets and to avoid color distortion, resolution failures and the like. By and large, therefore, offset art prints utilizing rasters or half-tone screens which must be angularly offset have relatively poor resolution.